The present invention relates to a method of selectively chlorinating the 3-position of 2-chloro-5-(trichloromethyl)pyridine by a non-catalyzed, liquid phase chlorination reaction resulting in the formation of 2,3-dichloro-5-(trichloromethyl)pyridine.
2,3-Dichloro-5-(trichloromethyl)pyridine is a well known compound useful as an intermediate in the preparation of agricultural chemicals, such as, for example, 2-(4-((3-chloro-5-trifluoromethyl)-2-pyridinyl)oxy)phenoxy propionic acid and derivatives thereof. Known methods of preparing 2,3-dichloro-5-(trichloromethyl)pyridine usually involve the use of a catalyst in a liquid phase chlorination reaction. See U.S. Pat. No. 4,331,811 which teaches and claims the use of tungsten, molybdenum and ruthenium catalysts.